re: I’m using the feature CSV Import and I don’t find a way to import and map a custom field.
You asking about the “Custom Fields” metabox and not custom fields, correct? Confusing, I know. Its kinda WordPress’s fault. Let me explain. On a new page/post you have a “Custom Fields” metabox … so does Connections when you add an entry. On a page/post you may have other fields added by the theme or plugin. For example for theme specific settings for the page or Yoast SEO. These too are custom fields. What make it even more confusing, the data for both are saved in the exact same place. Connections is the same too. You can have custom fields in addition to the “Custom Fields”. Clear (as mud, I’m sure)?
If you are asking about the “Custom Fields” metabox, sorry no, there is no way to map to them.
If you are asking about custom fields, yes, this is possible. Here’s a tutorial for on a custom text field. If has a section on how to register it with thee import and export tools.
Hope this helps!